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Purple pool problem!

Beatix's picture

This isn't a fine homebuilding question by anymeans, but I can't find a swimming pool forum, so I thought I'd try here.

We took our winter cover off of our inground pool yesterday, to find a fine, bright purple "soot" on the water side of the cover and covering the entire liner and stairs where the water touches. It brushes aside easily enough but I can't get it off of the pool light and stairs completely. I'm sure that it will stain and do a real number on the cartridge filter. Our pool company is coming out tomorrow to get the filter and lines going. But so far, they are stumped about the "purple" soot. I'm wondering if when they removed the cover last spring and folded it up while it was still wet, if this may have caused damage to the black side of the cover, causing it to deteriorate. It's just a guess. Now that the cover is dry, the purple "stuff" has turned chalklike. If anyone has any thoughts or experienced this, I'd really appreciate hearing about it. Thanks!

(post #53272, reply #1 of 96)

What color is the cover? 

What is the composition of the cover?  

Can you rub the backside of the cover with a white cloth and see a purple residue on that cloth? 

What chemicals do you use in your water treatment? 

more info please..................................................................Iron Helix

.......Iron Helix

(post #53272, reply #2 of 96)

This is called "purple big gulp pool syndrome" and is quite rare. Do nothing. Swim in the pool  as often as possible. You may even drink the water. Invite your  family and all your friends over for a midnight skinnydip.  

Remember the movie "Cacoon"?  It was actually this phenomenon that allowed those people to reverse aging.



(post #53272, reply #3 of 96)


Thanks for your response. The pool company came out, dropped their mouths open- I'm not kidding when I say that the pool was purple. Anyway they tested a sample and found our copper level to be sky high. So I've been vacumming on drain without the cartridges in, have drained and replaced 1/3 of the total volume, am vacumming some more and will bring another sample in tomorrow. Now my question is-where did the copper come from and how do I prevent this from happening again? Our heater is going to be checked-it's only 4 years old-yikes!

In answer to your questions-the liner is vinyl, black on the water side and blue on top. I'm working on washing the purple chalky residure off of it,  but I don't see anymore purple coming off it. I don't think it's the culprit anymore.

We use stabilized chlorine, shock, ph up and down when needed, that's about it. We had to increase the alkalinity once last summer.


I'd take the reverse aging in a flash-but right now I'm sure it would do the opposite. Our kids are dying to dive in, but we were told they'd turn green if they did!  :-) Could start a new trend!

Edited 5/2/2002 2:44:21 PM ET by Beatrix

(post #53272, reply #4 of 96)

There is copper in pressure treated wood. There is copper in sprays for fruit trees. You could have copper flashings on your roof or copper gutters that allow runoff to head to the pool. Your plumbing supply and recycle lines for the pumps and filters might be copper. Maybe the goldfish were pitching pennies made of copper all winter.

Excellence is its own reward!



Oh Well,

We did the best we could...

(post #53272, reply #5 of 96)

Did the pool company give any more detail than "copper"  Push for the details...

......Is it dissolved in the water, or is it deposited on the bottom?  Or both?

......What is your water source? Public or private well?

       In either case have it assayed for copper content.

.......The heater, I assume for the pool only, is it gas or electric?

        In either case it is hard for me to conceive of the heater contributing that much copper to create such a mass of color.

........What is the ph of the pool?   Many copper based chemicals respond to lower ph's and addition of muriatic acid may return them to the ionic form which may be colorless.  Try this in a white colored 5 gal bucket by adding acid.

still more detective work.........................................Iron Helix


ps.....................I recall seeing more compounds colored purple as a result of manganese as compared to specific is the pool companies test?

Edited 5/3/2002 7:01:03 AM ET by Iron Helix

.......Iron Helix

(post #53272, reply #6 of 96)

Use any Algecide last year??  If so, a dollar to a donut says that's where your copper is coming from.  If not, look elsewhere.  But I bet it's algecide.


How about clarifier??  That can cause problems too .. . . . .

(post #53272, reply #7 of 96)


We used a little (maybe 4 litres) of algecide and no clarifier last summer. I spoke to our pool company, they also said that algecide has copper in it, but the good quality stuff has very little. Luckily we used the good quality.


Yes-the detective work continues. What do you mean by "more details than just copper". I was told that the normal level of copper is 0 with an upper safe limit of .2ppm- our level started at 3.0, and was tested at 2.0 yesterday. I'm still vacumming on drain, lowering the water by 1/3 and filling it up again. There is now very, very little of the purple residue that can be seen.

The water was tested for:

-free, total and combined chlorine




-cyanuric acid



-total dissolved solids


The purple particles settle to the bottom but dissapate easily when brushed or vacummed too quickly. Our water is public, no one is the neighborhood with a pool has had this problem. The heater is gas and is 4 years old. It's a Teledyne-Laars. The pH and alkalinity are way off right now, since most of the water has been replaced. I had the water tested just before we closed in the fall-it was balanced then. They don't test for manganese. |Pardon my chemistry, it's been a while, but,would colorless copper in the ionic form still cause a problem?

I don't know if this has any significance, but, there's a new subdivision being built closeby. Last summer, when they were grading and digging, we had clouds of clay dust blowing directly at us. Instead of cleaning the cartridge filters 2 or 3 times a season, I was cleaning them twice a week when the dust was at it's peak. Everything was coverd in that fine red dust. Do you think this may have contributed to our problem?

The plan now stands to add 2 litres of "Mineral Out"- it doesn't say what it is made of and I didn't think to ask at the time. Then I have to add 24kg of alkalinity booster (baking soda), adjust the pH, shock the pool and have the water tested again. I'm hoping to bring in a water sample on Monday.

Please keep your thoughts and ideas coming, I really appreciate it!

(post #53272, reply #8 of 96)

Are you in an area that would allow access to a university chemistry department, or an independent assay lab?   If so consider hand filtering the"purple" stuff through a coffee filter, or rig your pump to accept a house type cartidge filter.  The residue on either filter can be tested using a sequential series of qualitative analysis tests or injected into a gas chromatograph for the identity of the Purple Pool culprit.

Your conjecture about the dust may have validity............back to an assay !

At any rate this is quite a conumdrom....I'm going to dig out my old chem books..........

I'll be back after a little memory refresher....??????....................Iron Helix

.......Iron Helix

(post #53272, reply #9 of 96)

Thanks again Iron. That is my plan. I drained the water onto the street and down the sewer and was very easily able to brush some purple powder that had collected at the end of our driveway, into plastic bags. I'll bring samples back to the pool company and to the lab run by the city. We hadn't thought of using a university lab, I have enough of the purple stuff for anyone who will take it! Did you by any chance read my muriatic acid dilemma about a year and a half ago? A friend of a friend is an excellant chemist who saved my butt then and who may have advice now also.

The pool looks great now, but we still haven't put the cartridges in the filter. I just vacumm and drain and then shut the system down.

Let me know what you come up with, I'd love to hear it!

Thanks again for your time,


(post #53272, reply #10 of 96)

ALLLL drained the pool.  Wash it down and start fresh. Alot cheaper than all those chemicals from the pool company. 

If you have some muriatic acid please try the following.......In a small glass container (a cup max) place 1/8 tsp of the purple powder(PP) to which add about 1/4 cup if water.  Into this mix add muriatic acid(straight from the bottle) at least a tablespoon by the drop and swirl. What I hope will happen is that the PP will go into solution with the high ph, or even change color to a clear solution. If no results I'm wrong on my assumption.  Be carefull with the acid...wear protection especially for your eyes.

So far the old dusty chem books have given me the following:

Most common copper compounds in crystaline form or solution are colored brown,  green or blue..... not purple.  This leads me to believe that although present in your pool in high concentrations it is probably not your culprit.

Although this does not rule out the presence of a copper complex of an unusual nature ...........I'm very rusty <g>on this topic...............see your local chemist.

Going back to the dusty closure of your pool and a passage from a discussion on manganese in the chem book. It talks about the production of potassium permanganate (intensely purple color) from manganese oxide (found in some clay soils) by combining it with chlorine in an alkaline solution.   This situation reminds me of closing a pool...............yours would already have the high dose of manganese oxide from the construction dust dissolved in the water to which you add cyuranic acid and super shock chlorine and cover the pool.  In the pressence of high chlorine and no sunlight to release the chlorine the water goes alkaline and the manganese oxid is converted to  PURPLE POWDER.   All this is speculation since it has been thirty+ years since I was in a lab.

So much for the smoke and mirrors BS.  With the powder in hand let a true chemist have a shot at a little qualitative analysis.  Most pool companies are very limited as to the real chemical analysis of any thing other than the common stuff.

Do keep me posted on the what the PP turns out to be...........................Iron Helix


.......Iron Helix

(post #53272, reply #11 of 96)

Well, you used high quality algaecide, so maybe that isn't it.  I do know though that the cheap stuff has a ton of copper in it. 

And I'm thinking here that Iron Helix has me outclassed in the chemistry department.  Other than a semester in college, chemistry is not my forte. 

Looks like you're on your way to figuring it out though.  Do let us know what you find.  I have a pool today and may one day have this problem !

(post #53272, reply #12 of 96)

Did you have them do a test for grape Kool-aid?










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(post #53272, reply #13 of 96)

at least you didn't say acid test


(post #53272, reply #16 of 96)

Wouldn't that be a Purple Jesus test???









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(post #53272, reply #18 of 96)

sounds electric to me


(post #53272, reply #15 of 96)

After having swimming pools for almost twenty years, I really thought that I had a decent level of understanding of them. This is turning out to be a real learning experience, to say that least.

Here's a link that may be helpful to you.

(post #53272, reply #14 of 96)


Here's the latest. Our copper level is now (thank God!!) zero-it was a labor intensive weekend that paid off. The question still remains, where did it come from? Could the half bottle of algecide have done it? We do dive for pennies occasionally, but that couldn't do it.

The pool company had a rep come in from the chemical company, who was quite amazed at the purple powder I had brought in. He was absolutley sure that the powder was not copper. The chemical company think that it may be bacterial-sounds bad, but, bacteria can be killed! I'm a nurse, I can do it!mThe heater is no longer being looked at as the bad guy. The friend of a friend chemist said right away that he feels it's a super bacteria. So I have to bring in a larger sample of the powder tomorrow and a fresh, water sample that they will culture for bacteria and run through a series of

Here's a link that points the purpleness at manganese, as you said right off the bat.

Your theory about the manganese coming from the clay is interesting. Our neighbors pool is fine though, but, he uses very little chlorine and keeps his pool very cold. Other pools are opening this coming weekend-some of the neighbors are worried after coming to see where the purple powder on the curb was coming from!

Lots left to do! I think a mineral purifier for the filter may be a wise purchase for us.

Edited 5/6/2002 10:57:31 PM ET by Beatrix

(post #53272, reply #17 of 96)

Wow......................what an interesting thread.  The answer will be anxiously awaited!  I hope it is not may have to have your pool sterilized.


Keep us posted...........................................Iron Helix

.......Iron Helix

(post #53272, reply #19 of 96)

Interesting doesn't describe it! :-)

The pool is now free of copper, balanced and is very clear, the water tested negative for manganese. I didn't drain the whole pool at once, but drained a third at a time and filled it up again- I did this 7 times. The purple powder is "wowing" everyone who sees it. I remain as pleased with our pool company as I have been since they built the pool. They are having 2 labs test and culture the water and powder. It really looks like the "bad guy" may be the clay dust blowing in from the construction site-if so, then we have to figure out a way of preventing it from happening again. I'm wondering if I should go over and get a sample of the clay and have it tested, for a comparision.

Your input has been great, thanks. Let's see what happens next!

(post #53272, reply #20 of 96)

Must be wonderful to breathe in that dust from the construction site, too.  Regardless whether it is making the purple powder or not,  the neighborhoods' lungs are taking a hit. 

Is that dust getting into the houses too? 






Quantum materiae materietur marmota monax si marmota monax materiam possit materiari?

(post #53272, reply #22 of 96)


Yes, I'm sure that we are breathing it in. Last summer, we all kept our windows closed and air conditioning on for more than we wanted to. Weekends were a little better when they weren't grading, but it was impossible to keep the windows and ledges clean. Most of the houses are in the process of being built now. They will be working on another field shortly, but it will become park areas and 3 baseball diamonds-the grading should be much quicker and hopefully less severe.

 It became standard last year that the neighbors would all warn each other when the winds were blowing this way. Outdoor patio furniture really took a beating. Allergy sufferers, suffered!

(post #53272, reply #21 of 96)

YES,GO TAKE A CLAY SAMPLE>>>>>>>>>>>>>>>>>>>have it analysed too!!

By the way, How BIG is your water bill going to be?

Keep the reports coming......................................Iron Helix

.......Iron Helix

(post #53272, reply #24 of 96)


I'm guessing about $200 worth of water so far, maybe more. The good news is that the filter has been running for the last 24 hours and NO MORE PURPLE!!! The water runs through the heater even when it's not on, (and it's not-it's going down to freezing tonight!). So far, so good.

I know from working in hospitals, that initial culture reports take 24 hours, we may get some results tomorrow.

How deep of a clay sample do you think I should get?

Edited 5/8/2002 9:27:53 PM ET by Beatrix

(post #53272, reply #26 of 96)

I assume that with ALL the dust as you have described that the topsoil was stripped away and held for a topcoat after the final elevations were to grade.  The sample should come from the  exposed subsoil which would contain more mineral and less organics......about a cups worth would be plenty.

And while your at it..... go ahead and take a topsoil sample just to be sure.

As this continues to unfold I have thoughts of the geothermal springs of Yellowstone and their myriad colors.   Some colors from mineral deposits, some from thermophilic bacterial with specialized metabolic pathways that produce intense colored deposits.

Maybe the process has been mimiced in a small way in your pool...............Iron Helix

.......Iron Helix

(post #53272, reply #27 of 96)

........the saga continues.

The Public Health Unit is testing the pool water (but this is now the chemically balanced water), not the original water with the purple in it. Their tests are limited though. Our pool company is sending the purple sediment to the chemical companies head office in Georgia. I have a chemical consulting firm looking in to our dilemma. They are going to research and ask around themselves before I go ahead and have the water, purple powder and clay soil from the construction site tested. That should cost about $200. But......I was told that they will do a mineral scan and microbiology culture but the interpretation of the results is up to us. Go figure!!

So far, everywhere I go, it's the same stumped look and "Wow, I've never heard of that before!"

And......the icing on the cake is that I have had the cartridges back in the filter and the system running since Wednesday, the water is crystal clear, but Friday's water result showed the copper level back up to 1.5. There is no way, right now, to bypass the heater, even when it's not in use- which makes me wonder if the copper is coming from the heater after all?????? I'll bring in another water sample on Monday.

The bump on the road is not getting any smaller yet  :-)

(post #53272, reply #28 of 96)

In a past response you mentioned the name of the heater company......pull out your product manual and look for a phone number.   Call these folks and ask what metals are used in the construction/manufacture of the unit that you own.  I  seriously doubt that they use anything but stainless steel in the heater due to the fact that chlorine and copper have a strong affinity for each other and a reaction is a given to produce Copper Chloride and dissolve away any copper or brass heater parts and turn your pool water green.

Ask them if they have had any PURPLE POOL problems!?!?!?!?

Let me digress back to Yellowstone and thermophilic bacteria.  Where else would you find such an environment in your pool system than in your heater?

I know that a chemical rule of thumb is that chemical reactions double for every 10  degrees of temperature increase.  Inside that heater would be an ideal situation as an incubator for chemical reactions or BIG SUPER BUGS.

If the pool was drained and cleaned was the heater disinfected or purged of sediments? Is the heater your TYPHOID MARY?   Mary was an OK person, but she was infected and ignorant of the may be your heater.

NO ANSWERS.........................only more questions......................Iron Helix


ps........sorry about having a little fun with Properos WP system !!!!!


.......Iron Helix

(post #53272, reply #29 of 96)

Well, we're still waiting and hoping for answers. The copper level is right back up again to where it was when we first opened the pool. The chemical company came out today and took more water samples to test. The heater company, Hayward (I mistakenly said it is was Teledyne Laars) is sending the manager out tomorrow to look inside of the heater. The warranty expired  2 years ago.

No other results back yet. The pool is clear (vey cold though since we won't turn the heater on until we know what's up). The bright side is that there is no further purpleness. Still keeping my fingers crossed that there is a relatively simple explaination and solution to this mystery....

(post #53272, reply #30 of 96)

All that data..............all those permutations.............!!!!!


I guess I'll wait till the next episode........................................Iron Helix

.......Iron Helix

(post #53272, reply #31 of 96)

Bandaids, but no real answers yet! The chemical company told me today that there is absolutely no manganese in the purple powder or the pool water-good news I guess. They remain stumped as to what the purpleness is and asked me if there was any way that a dye could have been introduced into the water accidently-perhaps from a new bathing suit or a towel thrown in. (Our neighbor next door does have a paint gun-but we're all friends) :-) Maybe the purple Kool-aid suggestion wasn't so far off after all!  :-)

The public health unit could not identify any bacteria in the water-also good news since we have been swimming in it for over a week.

The heater guy checked the heater and said that some damage may have been done by the alkalinity being low for a while last summer. I had the water checked every couple of weeks-when the alkalinity was low due to all of the rain, I raised it back up right away. But- the copper level still remains too high now. So to keep that from doing any damage, I just have to add a maintenance dose of "Cop Out" to keep the copper suspended and hopefully splashed out of the pool over time. Just a bandaid solution for now- but with no further answers-it's the best we can do.

Any more thoughts???

(post #53272, reply #32 of 96)

You still have not tested for Kool-Aid have you??!!

I don't want to say I told you so, but......

Hope you get your swimmin hole back before the warm weather!

Mr T








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